Air Force: an Answer to Our Power Needs May Be Blowing in the Wind

Listener 5 April, 2003.

Keywords: Environment & Resources; Growth & Innovation;

Lincoln University meteorologist, Neil Cherry, wonders aloud whether New Zealand is too windy to convert its wind power into electricity. Germany with the most wind power installations has winds averaging 6 metres/second. Denmark, the world leader in wind turbine manufacturing, has sites up to just over 7m/s, as has California the biggest wind power state in the US. A typical New Zealand site is 10m/s, which yields at least twice as much power. That means much more stress on the machinery. Half the European made gear boxes on one New Zealand wind farm had to be replaced within the guarantee period (and ten percent of them re-replaced).

Yet we need wind power. With the Maui gas field running down (although part of the reduction will be less petrochemicals exports and other gas fields will maintain domestic supply), the world target of reducing carbon dioxide emissions (which restricts the use of coal), and economic growth which will require more energy, New Zealand needs new electricity production. A particular concern is a few years out, when we may be more vulnerable to a dry year when the hydro-stations cant produce as much.

Wind power is likely to be cheaper than coal (even ignoring the consequences of greenhouse gases) if we can get them up and a-blowing. A major problem is the not-in-my-back-yard syndrome which has meant some prime sites have been turned down for planning permissions because the locals dont want a wind farm. Obviously there are some visually important sites which deserve protection – harbour heads would be near the top of my list – but NIMBYism can get ridiculous, while some of the claims, such that they are noisy, are not supported by overseas experience. There is a proposed amendment to the Resource Management Act before parliament to make planning approval for wind farms easier. (They are not always seen as a negative. The residents of Wellington’s Brooklyn are so proud of their wind turbine that it features as a pavement motif at the local shopping centre.)

There are no up-to-date government electricity projections for New Zealand, but a recent report prepared for the Ministry of Economic Development, Availabilities and Costs of Renewal Sources of Energy for Generating Electricity and Heat, provides some guidance. Depending upon various assumptions it expects that between a quarter and a third of the economically viable renewable energy (costing below 8c/kwh) available by 2025 will come from wind power. (Geothermal will contribute about two fifths, and most of the remainder (about a third) comes from hydro-electricity, with a very small biomass contribution, and solar power still too expensive. There may be only a limited additional contribution to the power supply from coal, because the cheap sources are located away from energy users.)

There is more wind energy available at above 8c/kwh. The total potential contribution from wind power could be as much as 4000MW, a figure to be compared with current installed electricity capacity from all sources of just over 8000MW. (World wind generation capacity stands at 31,000MW. Denmark, with a land area of Canterbury but somewhat flatter, plans to produce half of its electricity from wind by 2030.)

How much of that will be available depends upon costs as well as planning approvals. There is an active program of technological innovation to bring them down. One attempt involves a pilot 500 kW wind turbine at Gebbies Pass near Christchurch, the first of a planned ten. Its 33m two (rather than the standard three) rotor blades are made from laminated wood using technologies first designed for Americas Cup yachts, while New Zealander, Geoff Henderson (the chief executive of the company), has developed a torque limiting gearbox system to even out New Zealand’s strong winds. He initially designed it overseas, and the gearbox has been operating in windy UK sites for years. But he came home to develop it. So there is a couple of local technologies which if they succeed have export potential. (On the other hand all of the other installations are importing overseas technologies.)

Cherry heads Windflow’s board of directors, despite having motor neuron disease which has confined him to a wheelchair, limiting his life in environmental politics. His mind and spirit remain as active as ever, as he finishes off some key scientific papers and works with his family and friends preparing us for his early leaving. Meanwhile, he answers his own question of whether New Zealand is too windy for wind power by leading a practical New Zealand response.


Neil Cherry died in 24 May 2003 a week after he saw the prototype wind turbine commissioned at Gebbies Pass.

I have made a couple of small corrections of fact to the original article.